The collaboration with Breast Cancer Cure was pitched to the popular dairy producer and will be on New Zealand shelves from today. Twenty cents from each bottle will be donated to the charity, committed to finding a cure for breast cancer by 2018.

However, New Zealand Breastfeeding Authority chief executive Julie Stufkens said the move was disrespectful towards women.

"Sadly I think this is misguided advertising," she told stuff.co.nz.

"Labelling a cow's milk product as breast milk is not acceptable.

"The product does not contain any human milk and does not come from a breast but an udder."

Stufkens said she was concerned mother's could mistake the product as breast milk.

Lewis Road spokeswoman Angela Weeks said she's confident there won't be any confusion as the milk is clearly marked as "cow's milk" and is stocked in the chiller alongside the regular range of milks.

"The last thing we want to do is mislead customers which is why the bottle clearly states twice on the front that it is cow's milk and twice on the back," Ms Weeks told the Herald Online.

"We gave the Breastfeeding Authority a heads up to let them know about the campaign should they receive any enquiries.

"We hope that the steps we have taken will ensure people see this product for what it is - a way that people can support a charity that is committed to finding a cure for breast cancer."

The price of the milk hasn't changed, each 1.5 litre bottle is around RRP$6.10 from supermarkets.

Lewis Road made headlines last year after a collaboration with Whittaker's Chocolate that saw them craft a chocolate milk which attracted a cult following, selling out around the country.